Micro Flashcards
LCMV Name
Genome?
Enveloped/Naked?
Causes what?
Lymphocytic Choriomeningitis Virus
Arenavirus: ambisense, RNA, enveloped
Causes febrile, aseptic choriomeningitis
Groups of bacteria causing meningitis:
Pneumococcus
Group B Strep
Meningococcus
H. influenzae
4 Classic Symptoms of Meningitis:
- Headache
- Stiff Neck
- Fever
- Photophobia
Neisseria meningitidis: gram \_\_\_ \_\_\_\_cellular Oxidase \_\_\_ Catalyse \_\_\_ Ferments\_\_\_
Gram (-) Facultative intracellular Oxidase (+) Catalyse (+) Ferments Glucose and Maltose
Difference of pathogenic vs. non-pathogenic N. meningitidis strains:
Pathogenic = Encapsulated (polysaccharide)
Neisseria needs ___ agar to grow
Chocolate agar
N. meningitidis is:
Transmitted by ____
Colonizes ____
Airbone droplets
Nasopharynx (asymptomatic carriage)
Most common N. meningitidis age range:
2-18 years
3 major N. meningitidis virulence factors
- Polysaccharide Capsule
- IgA Protease
- LOS
Lack of what complement proteins increases risk for N. meningitidis
C5-9
Waterhouse-Friderichen Syndrome:
- Bilateral destruction of adrenal glands
- DIC
What can’t you give for N. meningitides?
Glucocorticosteroids
Group B Strep
Capsule?
Gram ___
___ Hemolytic
- Encapsulated
- Gram (+)
- Beta-hemolytic
Major risk group for GBS+ meningitis?
Why?
- Neonates
- GBS is natural flora in the vagina
CAMP test:
B-hemolysin of S. aureus interacts w/ GBS to cause enhanced hemolysis
Hippurase test turns what color?
Purple
2 Ways to differentiate GBS and Listeria in a CSF sample
- Morphology on gram stain (cocci vs rod)
- Motility on wet mount
Pneumococcus:
Gram ___
Catalase ___
___ Hemolytic
- Gram (+)
- Catalase (-)
- Alpha-hemolytic
Strep pneumonia is most common cause of community-acquired: (4 things)
- Pneumonia
- Bacterial meningitis
- Bacteremia
- Otitis media
Pnemococcus causes a (low/high) inflammation meningitis
High
- Strong inflammatory response
- All pathogenic strains produce a pneumolysin
Pneumococcal disease also requires what kind of testing?
Antibiotic-sensitivity testing
1st line Pneumococcus meningitis treatment is ___
If resistant, add ___
Vancomycin + ceftriaxone or cefotaxime
Resistant: add rifampin, meropenem or chloramphenicol
For which septic meningitises can you use corticosteroids?
Pneumococcal
3 routes of viral entry into CNS
- Neural
- Olfactory
- Hematogenous
80% of viral meningitis caused by:
Enterovirus
Brudzinski’s sign is:
- Guarding due to nuchal rigidity
- Neck raise –> leg raise
Distinguishing feature of encephalitis not found in meningitis
Encephalitis: intracerebral hemorrhage
What is ADEM?
When?
What causes?
- Acute Disseminated Encephalomyelitis
- postinfectious encephalitis (after VIRAL infection)
- 1-2 weeks later
- Autoimmune disorder
Herpes simple encephalitis usually affects what part of the brain?
- Temporal lobe
- Unilateral
When do you immunize someone for rabies?
- Post-exposure
- Prevents spread up into the brain
What is Pachymeninges
What is Leptomeninges
Pachy: outer layer, dura
Lepto: inner layer, arachnoid, dura
Lumbar Puncture CSF Findings in Bacterial vs Virus vs Fungal meningitis
Bacterial: high Neutrophils, low glucose
Viral: high Lymphocytes, normal glucose
Fungus: high Lymphocytes, low glucose
What do you have to worry about in terms of meningitis post-surgery?
Anaerobic bacteria
Clinical feature that distinguishes Meningitis vs Encephalitis
MENTAL STATE
confusion and/or decreased level of consciousness –>encephalitis
Pus in ____ (space) in acute bacterial meningitis
Subarachnoid space
3 Complications of Bacterial meningitis:
- Spreading to infect Virchow-Robbins (perivascular) space
- Thrombosis of leptomeningeal vessels
- Hydrocephalus (communicating or obstructive)
What kind of cell makes the BBB?
Astrocyte glial cells
“Worst headache in my life”
DDx: ruptured aneurysm
What kind of meningitis is usually self-limiting?
Aseptic (viral) meningitis
What is PML?
What causes it?
What can it be confused for
- Progressive Multifocal Leukoencephalopathy
- Viral by JC polyomavirus
- Can mimic MS
3 Major Patterns of Fungal Meningoencephalitis:
- Chronic Meningitis
- Vasculitis
- Parenchymal invasion
What 2 fungi are usually associated w/ vasculitis
Mucor (especially diabetics)
Aspergillus
What 2 fung are usually associated w/ brain invasion?
Candida
Cryptococcus
Rabies asociated w/ this animal
BATS!
Rabies encephalopathy pathopnemonic finding:
Negri bodies in brain
HIV encephalopathy has what finding:
Giant cells
Vasculitis meningitis can cause what superficial finding?
Petechial hemorrhages
